Titlting limb system for bows and crossbows and equipment formed therewith

ABSTRACT

A coupling system for limbs ( 3 ) of archery devices ( 1 ) such as bows and crossbows, includes a pair of limbs ( 3 ) joined at their ends by a bowstring ( 4 ) which is used for loading the energy to be released onto the arrow and to the center onto a support ( 2 ) of the device. In this system, the limbs ( 3 ) are hinged to the support ( 2 ) in such a manner as to be movable about an axis (A 1 ) of a pin ( 5 ) for fastening together the support ( 2 ) and the limbs ( 3 ); the axis (A 1 ) being perpendicular to the plane that passes through the limbs ( 3 ) and the bowstring ( 4 ).

The present invention relates to a tilting limb system for bows andcrossbows and equipment formed therewith.

At firing, the energy stored by a bow or crossbow is known to bereleased through the arrow via the bowstring and onto the centralsupport for bidirectional connection with the limbs.

While energy is required to be released onto the arrow, it should not bereleased onto the central support, because it generates strongvibration, disturbing the shooter and damaging with time the attitudeand mechanical balance of the archery device.

Manufacturers recommend to avoid firing without an arrow, which couldcause the limbs to break, because energy would be entirely released ontothe point of attachment of the limbs to the support thereby creating amechanical stress peak which causes them to break.

At present, certain limbs installed on bows and crossbows, of eitherrecurve or compound type, are allowed some adjustment but all arerigidly secured to the central support and remain integral therewith atfiring.

This problem may be obviated by using heavier arrows but, in spite ofthe high energy they release, these arrows have a slow flight withexcessive parabolas, which is exactly the opposite of what is currentlydesired: fast flight and straight trajectory.

The object of the present invention is to obviate the above drawbacks byproviding a novel limb fixation system for an archery device, such as abow or a crossbow, in which the limbs can tilt, with a unidirectionalconnection to the central support, to ensure self-absorption of thereleased energy, and protect the central support from such effect.

The present limb fixation system achieves the following advantages:

-   -   no vibration for the shooter,    -   long-lasting reliable mechanical attitude of the archery device,    -   no limb failure in case of dry fire,    -   possibility of using arrows of any weight,    -   improved performance with limbs having the same geometry and        power.

These objects and advantages are achieved by the coupling system forlimbs of archery devices such as bows and crossbows according to thisinvention, which is characterized by the annexed claims.

This and other features will be more apparent from the followingdescription of a few embodiments, which are shown by way of example andwithout limitation in the accompanying drawings, in which:

FIG. 1 is a general view of a crossbow having the limb coupling systemof the invention,

FIG. 2 is an exploded perspective view of the limb elements and theirsupport,

FIG. 3 is a sectional view proximate the support/limb coupling point,

FIG. 4 is a second sectional view proximate the support/limb couplingpoint,

FIG. 5 is a sectional view of three limb arrangements at firing,

FIG. 6 is a top view of the central area of the weapon as shown in FIG.1.

Referring to FIG. 1, numeral 1 generally designates an archery device,namely a crossbow, having a limb disengagement system of the presentinvention.

Hence, the crossbow 1 has a pair of limbs 3 mounted, as described below,to a support 2, which is in turn integral with the crossbow body; abowstring 4 connects the ends of the limbs 3 and allows energy to bereleased onto the arrow.

Referring now to FIGS. 2, 3 and 4, these show in detail the limb/supportcoupling system adapted to improve the performance of the device 1 byself-absorption of the released energy and protection of the centralsupport 2 from such effect.

As shown in the figures, the limbs 3, and particularly the hinges 7 forattachment of their ends, are coupled to the front of the support 2 byappropriate means, such as screws 8.

Therefore, each hinge 7 is integral with the end of its respective limband is coupled to the support 2 by means of a pin 5, which allows it topivot about the axis A1 of the pin for the limb to tilt relative to thepin 5; each pin 5 (and hence the axis A1) is obviously perpendicular tothe plane that passes through the limbs 3 and the bowstring 4.

Accordingly, by such coupling arrangement, the limbs are allowed topivot open through a few degrees forward, in the direction of arrow F1,as the bowstring 4 is released and then move back (in their returnstroke) towards the support 2, in the direction of arrow F2.

The above clearly shows that the support 2 acts as an abutment for thelimbs 3, to prevent them from excessively bending towards the center ofthe device 1 when the bowstring 4 is drawn: thus, the limbs 3 may flexat firing and be also retained by the support 2 as if they wereinterlocked therewith whereas, upon release (F1) they may pivot forwardsthrough a certain angle and accompany the arrow for a certain length ofits trajectory.

One or more pad means 6 with the ability of absorbing part of the storedenergy, are provided to prevent impacts against the support 2 during thereturn stroke.

Referring now to FIGS. 5 and 6, these show three different arrangementsC0, C1, C2 of the limbs 3 during the device loading step (C1), thepushing and releasing step (C2) and the rest or repositioning step (C0)

As shown from FIG. 5, the limb system as described above, as comparedwith a bow of identical power and geometry, allows the stroke to beincreased by an amount C, which provides increased thrust: the longerthe stroke the faster the arrow.

The center-to-center A of the limbs 3 can decrease but not increase,because it is limited by the maximum length of the bowstring 4.

1. A coupling system for limbs (3) of archery devices (1) such as bowsand crossbows comprising a pair of limbs (3) joined at their ends by abowstring (4) which is used for loading the energy to be released ontothe arrow and to the center onto a support (2) of the device,characterized in that said limbs (3) are hinged to the support (2) insuch a manner as to be movable about an axis (A1) of a pin (5) forfastening together said support (2) and said limbs (3); said axis (A1)being perpendicular to the plane that passes through the limbs (3) andthe bowstring (4).
 2. A system as claimed in claim 1, characterized inthat it provides one or more pad means (6) interposed between thesupport (2) and the limb (3) for absorbing part of the energy during thereturn stroke of the limb.
 3. An archery device (1), such as a bow or acrossbow, comprising a pair of limbs (3) joined at their ends by abowstring (4) which is used for loading the energy to be released ontothe arrow and to the center onto a support (2) of the device,characterized in that the limbs (3) are hinged to their support (2) bycorresponding pins (5) to pivot about the axis (A1) a few degreesforward (F1) upon release of the string (4) and then reposition itself,during the return stroke (F2), to abutment against the support (2),which acts as an abutment member for the limbs (3), thereby preventingthem from excessively bending back to the center of the device (1) whenthe bowstring (4) is drawn.
 4. A device (1) as claimed in claim 3,characterized in that it comprises one or more pad means (6) between thesupport (2) and the limb (3) for absorbing part of the energy during thereturn stroke of the limb.